Many surgical procedures require a median sternotomy, a procedure in which an incision is made along the sternum such that it can be separated laterally into two sides. This allows access to the tissues and organs located in a patient's thoracic cavity. Following the surgical procedure, the two sides of the sternum must be closed. When a medical emergency occurs after the sternum has been closed, physicians need to be able to immediately reopen the sternum to access the patient's thoracic cavity.
Closure of the sternum was traditionally performed using wire based closure systems. Stainless steel wires were wrapped around or through the sides of the sternum to secure the sides together. Wire based closure systems have several recognized deficiencies. Their attachment is time consuming, averaging 15-20 minutes, and they do not allow for quick access to the thoracic cavity in cases where emergency re-entry is necessary. Wire based closure systems also promote post-surgery complications including patient pain, infection, and problems with healing caused by the wire loosening and allowing the sides of the sternum to slide with respect to each other. Such complications often require the patient to undergo a follow-up surgical procedure.
Other types of closure systems have been developed as alternatives to wire based closure systems. For example, clamp closure devices and plate closure devices are newer sternal closure technologies.
U.S. Pat. No. 6,007,538 discloses a pair of slidably associated J-shaped clamp members. The curved end of each clamp member wraps around one of the patient's ribs, and the straight ends extend across the fracture and overlap one another. The straight ends have threaded holes, and the holes of the two straight ends are aligned to receive screws. The sternum may be reopened by removing the screws from the clamp members on each side of the sternum and sliding the clamp members away from each other.
U.S. Pat. No. 7,033,377 discloses a clamp closure device wherein the clamp members are held together by a rotary lock member. The sternum may be reopened by using a plier-like tool to open the rotary lock and then a prying tool to force the clamp members apart.
U.S. Pat. No. 7,052,499 discloses an elongated plate with two regions suited to receive fastening devices for fixation to the sternum, and a bridge region therebetween. The sternum can be reopened by cutting the bridge region, which is designed for such cutting.
U.S. Pat. No. 6,872,210 discloses a sternum closure device with two overlapping plates or clamps that are held together by a release member. Movement or removal of the release member allows for separation of the two sides of the sternum.
These examples and other sternum closure devices have numerous deficiencies. For example, due to cumbersome release mechanisms, the prior art devices may not have smooth edges or a low profile for minimizing patient discomfort; the release member may not be flush with the top and/or side surfaces of the device, thereby leaving a protruding object in the patient's chest; and opening the device may be too time consuming to allow the physician immediate access to the thoracic cavity in case of medical emergency. Opening the device may involve ruining the device itself requiring a new device to re-close the sternum, which is costly and time consuming. Opening or removing the device may involve multiple tiny pieces, such as screws, that are hard to manipulate and can get lost in the patient's body. Further, when screws have to be removed to open the device and then re-inserted into the bone to re-close the sternum, it results in weaker fastening of the device to the sternum. Alternatively, the device may have a design that allows for quick reopening, but compromises stabilization of the opposing sides of the sternum, which is important during healing. It would, therefore, be desirable to provide a new and improved sternum closure device that overcomes these drawbacks and limitations.